I grew up in NY, been to Cali a bunch. Live in Atl now. Everywhere, everything is high now. Cali has always been high for everything. What else is new? lol!

 

Interesting read indeed….

Joe Z

 

Years ago we installed a RCF throttlebody (which is like 6mm bigger than ISF throttlebody) and ported intake manifold on an FBO ISF and real gains were minimal, like 3-4hp, certainly not worth the effort. The 84mm throttle body size on RCF is decent, and you cant port it much so I don't think the gains would be much more than we saw on ISF.

Literally no one has been able to show objective results showing any power gained from those expensive high power ignition coils. I even contacted a company asking for a set at cost in return for future orders once I perform testing, they don't even reply to my multiple inquiries, LOL. The notion that coils will make power on our NA engine when we don't even have any ignition issues under boost is rediculous. I would be suspicious of anyone trying to sell you expensive ignition coils.

Rafi

 

We have literally tested every exhaust available for RCF, both with and without supercharger. There is absolutely no difference between 2.5" dual, 2.75" dual (invidia), or 3" dual (ARH).... going bigger does not improve power NA or at our current SC power levels.

We have shown that exhausts make power, no one is questioning that. But the GTHaus 40hp claims are pure fraud.

Rafi

 

Ok so I did not say a Enlarged Throttle Body, Nor different TB. That's different and of course you would see a different result with a mod different than what I stated. You now have changed the topic. I also did Not say a totally different Drastic change TB either? Did I?

I love always seeing the general consensus with no test or data that hotter ignition won't work. Now hang on..... they don't work so you say But .......you tried to get some for free, but it's ridiculous is really - lol! To me. So you have never tested them? Ok! So help me out here? You contact a company for a reason to buy and test something you know is ridiculous, and you advise me to be suspicious on what you actually wanted to Buy to try?

I never understand the conclusion with no trial or data to back it up? With that, there are many different N/A cars that Hot Rod magazine and Nopi and other JDM tuners tried N?A Cars, and they did in fact produce a gain in spite of the "coils dont work on n/a", blanket statements. Backed up by data and Dyno runs. Dyno's are in fact what you sell lots of your own performance parts by claims on, even in spite of some getting those gains, and some not, correct.? The Ignition could be many things. Do you think a complete burn across in the cylinder results in hp if the car has had a lot of performance mods changes vs stock? Do you make changes in ignition to your Tunes? lol!

Again below is what I said:

Originally Posted by jgscott View Post
How about, Port/Clean up the Upper and Lower Intake Manifold? Maybe Polish the TB Too!!!

How about some Hotter Ignition Coils tested too?

 

I keep going back to the stock 419 whp for the RCF especially for 100,000 mile car. Kudos to RR racing for not sandbagging the results as typically we see 400 whp for stock RCF dynos. Maybe, RR racing might know, but is it because of Octane 93 allowing car to run stronger or is it because the Dyno number are STD rather than SAE corrected? Or Maybe, this car is just running stronger than RCFs do on the average?

 

What caught my eye RR racing is running dyno tests at 4th gear, that will net you higher numbers than normal. Most people dyno at 5th gear which is the closest you can get to 1:1 ratio. At least RR racing gives full disclosure as opposed to numbers popping magically from nowhere which is refreshing to see.

 

Did you mean 6th gear ??

Which is the perfect 1:1 ratio for the IS F / RC F..

Joe Z

 

I meant relative to using 4th gear.

6th will place you at the 1:1 ratio but for all practical reasons you will not be able to wring out the most from the engine, speed limiter will kick in too early. 5th gear while not being exactly 1:1 ratio it's the closest you can get to it and allow you to maximize the entire rev band.

 

13 years ago owners were easily independently dyno’ing their IS F’s with +25 Rwhp gains with intake & exhaust upgrades utilizing 6th gear..

No issues whatsoever

Man I can’t believe it’s been that long…..

Joe Z

 

Interesting to know that about the IS F's.

RCF seems to run into issues with the 6th gear continuing to climb but then cut short as it hits speed limiter too early. I personally had to dyno mine on 5th gear.

 

Not sure I understand A lower gear (5th) will reach redline before a higher gear (6th). I dynod my ISF in 6th, I'd expect an RCF to react the same way. Both have 2.94 rear ends with the same transmission.

 

Redline is the difference. ISF hits peak power at 6600 rpm and RCF hits peak power at 7100 rpm. RCF hits 168 mph speed limiter in 6th before it hits redline so peak power cannot be measured.

 

^^^^Yes just as Rolla explained, we are not talking about redline but with the 6th gear speed limiter is hit before you can get to the higher RPM range where the RCF is suppose to be arriving at peak HP. I couldn't have said it any better than Rolla just did.

Other than the difference in redline the ECU mapping on the RCF is different than on the ISF therefore power band is different, it's not a question of similarity in gearing.

If you search on this forum you will come across Gunny who clearly ran into this issue with his RCF. His dyno test was run with 6th gear. I don't understand why his dyno guy didn't recognize the issue and remedy it by going one gear down. I personally had to dyno mine with 5th gear. Successful dyno runs with the RCF I have seen are either ran on 5th or 4th.

 

Great follow up guys… that’s correct on the raised redline for the RC F / GS F

First Gear Ratio (:1) 4.60

Second Gear Ratio (:1) 2.72

Third Gear Ratio (:1) 1.86

Fourth Gear Ratio (:1) 1.46

Fifth Gear Ratio (:1) 1.23

Sixth Gear Ratio (:1) 1.00

Seventh Gear Ratio (:1) 0.82

Eighth Gear Ratio (:1) 0.69

Joe Z